1. Field of the Invention
The present invention relates to a solid-state imaging device, a camera, an electronic apparatus, and a method for manufacturing a solid-state imaging device.
2. Description of the Related Art
Cameras, e.g., digital video cameras and digital steel cameras, include solid-state imaging devices. For example, a charge coupled device (CCD) type image sensor is included as the solid-state imaging device.
For example, in the CCD type image sensor, an imaging region, in which a plurality of pixels are arranged in the matrix in a horizontal direction and a vertical direction, is disposed on a surface of a substrate. In this imaging region, a plurality of photoelectric conversion portions to receive the light based on a subject image and generate signal charges are disposed in such a way as to correspond to the plurality of pixels. For example, a photodiode is disposed as this photoelectric conversion portion. A microlens is disposed above the photoelectric conversion portion, and the photoelectric conversion portion is configured to receive the light incident through this microlens.
Furthermore, vertical transfer register portions are disposed between lines of a plurality of photoelectric conversion portions aligned in the vertical direction in the imaging region. The vertical transfer register portion includes a plurality of transfer electrodes disposed opposing to vertical transfer channel regions with a gate insulating film therebetween and transfers the signal charge read from the photoelectric conversion portion by a charge readout portion in the vertical direction. Then, the signal charges, which are transferred by the vertical transfer register portion on a horizontal line (pixels in one line) basis, are transferred in the horizontal direction sequentially by a horizontal transfer portion, and are output by an output portion (refer to Japanese Unexamined Patent Application Publication No. 2002-359363, for example).
Furthermore, in the imaging region, a metal light-shield layer is disposed in such a way as to block the light incident on the vertical transfer register portion in order to prevent an occurrence of a problem, e.g., a smear.
In the above-described solid-state imaging device, an alias referred to as a flare or a ghost may occur. For example, in the case where the incident light is reflected diffusely by a reflection layer, e.g., a metal light-shield layer, and enters the photoelectric conversion portion, an alias may occur.
In order to prevent an occurrence of an alias, it has been proposed that a black color resist pattern layer, which is referred to as on chip black (OCB) and which serves as a light-shield layer, is further disposed above the metal light-shield layer (refer to Japanese Unexamined Patent Application Publication No. 2007-324481 and Japanese Unexamined Patent Application Publication No. 2004-356503, for example).
Moreover, a color filter is disposed above the above-described photoelectric conversion portion, and the light colored with this color filter is received by the photoelectric conversion portion. The color filter includes, for example, color filters of three primary colors, and the color filters of three primary colors are arranged in the Bayer pattern. In addition, a microlens is disposed above the color filter and the light condensed with this microlens enters the photoelectric conversion portion through the color filter (refer to Japanese Unexamined Patent Application Publication No. 2001-267543, for example).
Besides, it is proposed that an intralayer lens is disposed between the photoelectric conversion portion and the microlens. The intralayer lens is disposed to apply the light incident through an on-chip lens to the photoelectric conversion portion efficiently (refer to Japanese Unexamined Patent Application Publication No. 2004-304148 and Japanese Unexamined Patent Application Publication No. 11-103037, for example).
Furthermore, in the above-described solid-state imaging device, in order to cut infrared rays other than visible rays from the incident light, an infrared cut filter is disposed.
The infrared cut filters are roughly divided into a light absorption type, e.g., color glass filters, and a light reflection type by using an inorganic interference multilayer film.
FIG. 2 is a diagram showing a spectral transmission characteristic of an infrared cut filter. In FIG. 2, a broken line indicates the case of the light absorption type, and the solid line indicates the case of the light reflection type.
As indicated by the broken line shown in FIG. 2, in the case of the light absorption type, infrared rays are cut through absorption of the infrared rays. The light in the wavelength range out of the cut wavelength range corresponding to the infrared rays may be absorbed to a large extent. On the other hand, as indicated by the solid line shown in FIG. 2, in the case of the light reflection type by using an inorganic interference multilayer film, the light in the wavelength range out of the cut wavelength range is almost transmitted. Specifically, the light having a red component is transmitted by the light reflection type to a large extent as compared with that by the light absorption type.
Consequently, regarding the solid-state imaging device, the infrared cut filter of the light reflection type by using an inorganic interference multilayer film is used favorably in order to improve the sensitivity (refer to Japanese Unexamined Patent Application Publication No. 2005-109196, for example).